title: Human β-defensin 3 (DEFB103) and its influence on Staphylococcus aureus nasal carriage.
abstract: OBJECTIVE
  The DEFB103 gene encodes human β-defensin 3, which has a high activity against Staphylococcus aureus. In the general population 20% are persistent nasal carriers of S. aureus, which is a problem for their general health. DEFB103 shows extensive variation in copy number. Copy number variations (CNVs) are believed to play a role in susceptibility to certain diseases. The possible associations between CNVs, mRNA, and nasal S. aureus carriage status were investigated.
  
  
  METHODS
  We used the pyrosequencing-based paralog ratio test to determine the DEFB103 copy number. Nasal swabs were collected for RNA and S. aureus determination. S. aureus genotypes were determined by spa typing, and real-time PCR was used to determine DEFB103 mRNA expression.
  
  
  RESULTS
  The DEFB103 CNV varied from 2 to 8 copies per diploid genome. No significant difference in copy number was observed among the groups. We found 74% of the volunteers to be non-carriers, 20% to be persistent carriers, and 6% to be intermittent carriers. The S. aureus isolates linked to more than 16 clonal lineages. mRNA expression varied extensively, but no significant differences were observed between the groups. We did not find a linear correlation between CNV and mRNA expression.
  
  
  CONCLUSIONS
  The results indicate that DEFB103 CNV does not influence S. aureus carrier status.
authors.affiliation: Laboratory of Microbial Pathogenesis and Host Susceptibility, Department of Microbiological Surveillance and Research, Statens Serum Institut, 5 Artillerivej DK-2300 Copenhagen S, Denmark.
authors.forename: Peder
authors.initials: P
authors.lastname: Fode
authors.forename: Marc
authors.initials: M
authors.lastname: Stegger
authors.forename: Paal Skytt
authors.initials: PS
authors.lastname: Andersen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002353:Carrier State / Q000382:microbiology*; D005260:Female; D018628:Gene Dosage; D014644:Genetic Variation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009296:Nasal Cavity / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D023083:beta-Defensins / Q000235:genetics* / Q000502:physiology*
chemical_list: C422950:DEFB103A protein, human; D012333:RNA, Messenger; D023083:beta-Defensins